Display devices such as liquid crystal displays (LCD) and organic electroluminescent devices (OLED) have become necessities in people's life. With the increase of people's requirements, in order to improve display quality of the display device and avoid the deviation in box aligning of the array substrate and the color film substrate from influencing the aperture opening ratio of the display device and the problem of light leakage, the integration technology of integrating the color filter and the array substrate together, i.e., color filter on array (Color Filter on Array, COA) emerges as the times require. The COA technology is namely arranging the black matrix and the color filter on the array substrate.
As shown in FIG. 1, in the existing COA substrate, the color filter 9 is not arranged at the position above the black matrix 8, the common electrode layer 11 is arranged on the black matrix 8 directly, since the film thickness of the color filter 9 is relatively large, the “section difference phenomenon” will be produced, such that the total film thickness between the common electrode layer 11 and the data line 14 will be relatively small, consequently, a relatively large parasitic capacitance will be generated between the data line and the common electrode layer, a relatively large signal delay will be generated, and the image display quality of the display will be reduced.